Track ball

ABSTRACT

A track ball capable of preventing foreign matter such as water and dirt from entering the inside of a case having a sensor substrate stored therein, wherein a rotating body ( 4 ) and a rotation sensor ( 5 ) are installed separately from each other through the case ( 2 ) so that the foreign matter such as water and dirt can be prevented from entering from a ball side space (SB) continued with an environment on the outside of the track ball into a case internal space (SI) having the sensor substrate ( 6 ) stored therein, and the case portions ( 2 A) and ( 2 B) of the case ( 2 ) separating at least the rotating body ( 4 ) and the rotation sensor ( 5 ) from each other and forming a part of an electromagnetic wave transmission route for detecting detected electromagnetic wave by the rotation sensor ( 5 ) can transmit the electromagnetic wave detectable by the rotation sensor ( 5 ).

TECHNICAL FIELD

The present invention relates to a track ball and, more particularly, toa track ball capable of preventing foreign matters such as water anddust from intruding into a case containing a sensor board.

BACKGROUND ART

A track ball, which is a pointing device for a computer and othervarious types of digital equipment, is configured so that by rotating aball in an arbitrary direction with a palm or fingers, rotation isdetected smoothly and continuously, and hence precise position controlcan be carried out easily.

FIG. 3 is an explanatory view showing a side sectional construction of aconventional track ball. In FIG. 3, the conventional track ball has: aball support structure 37 having a rotating shaft 3 which supports aball and transmits the rotation of the ball and a rotating element 34for causing a rotation sensor 35, described later, to read the rotationof the rotating shaft 3; the rotation sensor 35 which generates a pulsesignal by detecting the rotation of the rotating element 34 in the ballsupport structure 37 and transmits the pulse signal to a sensor board 6,described later; the sensor board 6 for arithmetically operating thetransmitted pulse signal to detect the rotational displacement; a case32 which is a housing structure for the track ball and protectivelycontains the sensor board 6 therein; and the ball (not shown), which isan input operation part. By this configuration, the rotation of ballproduced by the operation of a palm or the like is transmitted to therotating shaft 3 and is changed to the rotation of the rotating element34. The rotation of the rotating element 34 is changed to a pulse signalby the rotation sensor 35, which can be detected as rotationaldisplacement including direction after being subjected to processing bythe sensor board 6.

In FIG. 3, the rotating element 34 of a disc shape formed with a slit isprovided at the end of the rotating shaft 3 for transmitting therotation of ball so that a part of the rotating element 34 enters a caseinterior space SI in the case 32 containing the sensor board 6 from aball-side space SB through a notch 8 provided in the case 32.

The rotation sensor 35, which is a transmission photosensor, has pairedportions serving as a light emitting portion and a light receivingportion provided with the rotating element 34 being held therebetween,and the rotating element 34 is provided so as to be positioned betweenthe paired portions. By this configuration, the ball-side space SB andthe case interior space SI existing with the case 32 being a boundarytherebetween are configured so as to communicate with each other throughthe notch 8 provided in the case 32.

A problem with the conventional track ball is that the presence of notchallows water, dust, dirt, and the like to intrude into the case from theball-side space continuous with the environment on the outside of thetrack ball through the notch (X3 in FIG. 3), and these foreign mattersadhere to the sensor board, and exert an adverse influence on theperformance and normal operation of the sensor board, which results in adecrease in detection accuracy of track ball.

The present invention has been made to solve the problem with the priorart, and an object thereof is to provide a track ball capable ofpreventing foreign matters such as water and dust from intruding intothe case containing the sensor board.

DISCLOSURE OF THE INVENTION

The inventor conducted studies earnestly on the above-describedproblems, and resultantly concluded that the isolation of the caseinterior space from the ball-side space is effective in preventing theintrusion of foreign matters, and therefore, the above-describedproblems can be solved by taking measures capable of detecting therotation expressed in the rotating element even in such a construction.The invention claimed in this application as measures for solving theabove-described problems is as follows:

(1) A track ball having a ball; a ball support structure having arotating shaft which supports the ball and transmits the rotation of theball and a rotating element which is provided at the end of the rotatingshaft to cause a rotation sensor, described later, to read the rotationof the ball; the rotation sensor which generates a pulse signal bydetecting the rotation of the rotating element that expresses therotation of the rotating shaft and transmits the pulse signal to asensor board, described later; the sensor board for arithmeticallyoperating the transmitted pulse signal to detect the rotationaldisplacement; and a case which is a housing structure for the track balland protectively contains the sensor board therein,characterizedinthattherotatingelementandtherotationsensorareprovided soas to be isolated from each other, and of the case, at least a portion,which forms a part of an electromagnetic wave transmission path for therotation sensor to detect an electromagnetic wave to be detected, has aconstruction capable of transmitting an electromagnetic wave that can bedetected by the rotation sensor.

(2) The track ball described in item (1), characterized in that thewhole of the case has a construction capable of transmitting theelectromagnetic wave.

(3) The track ball described in item (1) or (2), characterized in thatthe case has no notch for the rotation sensor to detect the rotation ofthe rotating element.

(4) The track ball described in any one of items (1) to (3),characterized in that the electromagnetic wave is visible rays, and theconstruction of the case for transmitting the electromagnetic wave is atransparent or semitransparent visible ray transmitting construction.

(5) The track ball described in any one of items (1) to (3),characterized in that the electromagnetic wave is infrared rays, and theconstruction of the case for transmitting the electromagnetic wave is aninfrared ray transmitting construction.

(6) The track ball described in item (4) or (5), characterized in thatthe rotating element has a disc shape, the rotation sensor is atransmission photosensor, and the side sectional shape of the case in aportion in which the case is opposed to the peripheral edge portion ofthe rotating element (hereinafter referred to as “element portion”) issubstantially in a U shape having a U-shaped portion.

(7) The track ball described in item (4) or (5), characterized in thatthe rotating element has a drum shape, and the rotation sensor is areflective photosensor.

(8) A dustproof and waterproof track ball characterized in that foreignmatters are prevented from intruding into the interior of the casecontaining the rotation sensor by the track ball described in any one ofitems (1) to (7).

In the present invention, as a material for the case of track ball,there is used a material capable of transmitting an electromagneticwave, which is an object to be detected by the rotation sensor, such asa transparent or semitransparent visible ray transmitting material or aninfrared ray transmitting material. Therefore, there is no need forproviding a notch, the rotation sensor and the sensor board are providedso as to be isolated completely from the support structure forsupporting the ball, and foreign matters such as water, dust, and dirtare prevented from intruding to the sensor board side, by which thedurability and reliability of track ball are improved, and theabove-described problems are solved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory view showing a side sectional construction of atrack ball in accordance with the present invention;

FIG. 2 is an explanatory view showing a side sectional construction ofanother example of a track ball in accordance with the presentinvention; and

FIG. 3 is an explanatory view showing a side sectional construction of aconventional track ball.

Symbols used in these figures designate the followings. 2, 22, 32 . . .case, 2A, 2B, 22C . . . case portion, 3 . . . rotating shaft, 4, 24, 34. . . rotating element, 5, 25, 35 . . . rotation sensor, 5A, 5B . . .rotation sensor portion, 6 . . . sensor board, 7, 27, 37 . . . ballsupport structure, 8 . . . notch, E . . . light emitting portion, L, L′. . . path of visible light etc., R . . . light receiving portion, SB .. . ball-side space, SI . . . case interior space, X1, X2, X3 . . .movement flow of foreign matters.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will now be described in detail with reference tothe accompanying drawings. The present invention is not limited to theembodiment described below. In the figures, the same symbols are appliedto the same elements to give explanation.

FIG. 1 is an explanatory view showing a side sectional construction of arotating element and its surrounding portion of one example of a trackball in accordance with the present invention. FIG. 1 shows an examplein a case where a transmission photosensor is used as a rotation sensor5. In FIG. 1, the track ball in accordance with the present inventionhas a ball support structure 7 having a rotating shaft 3 which supportsa ball (not shown), being an input operation part, and transmits therotation of the ball and a rotating element 4 which is provided at theend of the rotating shaft 3 to cause the rotation sensor 5, describedlater, to read the rotation of the ball; the rotation sensor 5 whichgenerates a pulse signal by detecting the rotation of the rotatingelement 4 that expresses the rotation of the rotating shaft 3 andtransmits the pulse signal to a sensor board 6, described later; thesensor board 6 for arithmetically operating the transmitted pulse signalto detect the rotational displacement; and a case 2 which is a housingstructure for the track ball and protectively contains the sensor board6 therein. The rotating element 4 and the rotation sensor 5 are providedso as to be isolated from each other by the case 2 so that foreignmatters such as water and dust can be prevented from intruding into acase interior space SI containing the sensor board 6 etc. from aball-side space SB, which is a space continuous with the environment onthe outside of the track ball. Also, of the case 2, at least caseportions 2A and 2B (both 2A and 2B are closely hatched portions in FIG.1), each of which isolates the rotating element 4 from the rotationsensor 5 and forms a part of an electromagnetic wave transmission pathfor the rotation sensor 5 to detect an electromagnetic wave to bedetected, has a construction capable of transmitting an electromagneticwave that can be detected by the rotation sensor 5.

Herein, the electromagnetic wave transmission path is a path throughwhich an electromagnetic wave such as visible rays or infrared raystravels.

In FIG. 1, this track ball can be configured so that the whole of thecase 2, not limited to the case portions 2A and 2B, can have aconstruction capable of transmitting the electromagnetic wave. Also,unlike the conventional example, the case 2 need not be provided with anotch (refer to FIG. 3) for the rotation sensor 5 to detect the rotationof the rotating element 4.

In FIG. 1, the track ball has a construction such that the rotatingelement 4 has a disc shape formed with a slit, the rotation sensor 5 isa transmission photosensor, and the side sectional shape of the case 2in a portion in which the case 2 is opposed to the peripheral edgeportion of the rotating element 4 (hereinafter referred to as “rotatingelement portion”) is substantially a U shape having a U-shaped portion.

In the track ball shown in FIG. 1, the rotation sensor 5, which is thetransmission photosensor, has portions 5A and 5B provided with a lightemitting portion and a light receiving portion that are opposed to eachother with the rotating element 4 being held therebetween, and therotating element 4 is provided so as to be positioned between theportions 5A and 5B. The ball-side space SB in which the ball supportstructure 7 is provided and the case interior space SI in which therotation sensor 5 and the sensor board 6 are provided are isolated fromeach other with the case 2 being a boundary. Therefore, the rotatingelement 4 and the rotation sensor 5 are provided in a state of beingisolated from each other by the case 2, and the rotation sensor 5 andthe sensor board 6 are constructed so as not to communicate with theball-side space SB, that is, so as to be isolated from the space. SB.

When visible rays are utilized as the electromagnetic wave, the trackball shown in FIG. 1 can be constructed so as to transmit theelectromagnetic wave by making the case 2 have a transparent orsemitransparent visible ray transmitting construction. To obtain such aconstruction, the whole of the case 2 or at least the case portions 2Aand 2B can be constructed by using a transparent or semitransparentmaterial.

The term “semitransparent” in the present invention includes a largedegree of transparency as long as visible rays of a degree enough tokeep the function of track ball can be transmitted.

When infrared rays are utilized as the electromagnetic wave, the trackball shown in FIG. 1 can be constructed so as to transmit theelectromagnetic wave by making the case 2 have an infrared raystransmitting construction. To obtain such a construction, the whole ofthe case 2 or at least the case portions 2A and 2B can be constructed byusing an infrared ray transmitting material. When other electromagneticwaves are utilized, similarly by making the case 2 have a constructioncapable of transmitting that electromagnetic wave, the same effect canbe achieved.

In FIG. 1, since the track ball in accordance with the present inventionhas the above-described construction, the rotation of the rotatingelement 4 of the ball support structure 7 provided in the ball-sidespace SB is detected through the case portions 2A and 2B capable oftransmitting an electromagnetic wave that can be detected by therotation sensor 5, for example, visible rays or infrared rays, orthrough the case 2. Specifically, in FIG. 1, when the portion 5A of therotation sensor 5, which is a transmission photosensor, is the lightemitting portion and the portion 5B thereof is the light receivingportion, the electromagnetic wave such as visible rays or infrared raysemitted from the light emitting portion 5A enters the disc-shapedrotating element 4 existing in the ball-side space SB region through thecase portion 2A of the case 2, being processed by the slit provided inthe disc, and is received and detected as a pulse signal by the lightreceiving portion 5B through the case portion 2B. In FIG. 1, forexample, on a straight line L, there exists a path (electromagnetic wavetransmitting path) through which visible rays etc. go from the lightemitting portion 5A to the light receiving portion 5B through the caseportions 2A and 2B.

Since the rotating element 4 need not be provided so as to enter thecase interior space SI for the rotation sensor 5 to detect the rotationof the rotating element 4, the case 2, which is the boundary betweenboth of the spaces SB and SI, need not be provided with a notch forcausing these spaces SB and SI to communicate with each other.Specifically, the ball-side space SB in which the ball support structure7 is provided is isolated from the case interior space SI containing therotation sensor 5 and the sensor board 6 by the case 2. Therefore,foreign matters such as water and dust can be prevented from intrudinginto the case interior space SI from the ball-side space SB continuouswith the environment on the outside of the track ball.

In other words, even if foreign matters such as water and dust, whichare originated from the environment on the outside of the track ball,are present in the ball-side space SB, the foreign matters do notintrude into the case interior space SI, which is isolated from theball-side space SB by the case 2 (X1). Therefore, the foreign mattersare prevented from intruding into the sensor board 6 and the rotationsensor 5, which are provided in the space SI.

The rotation of the rotating element 4 is detected by the rotationsensor 5 provided in the case interior space SI, and a pulse signal isgenerated by the rotation sensor 5. The pulse signal is transmitted toand arithmetically operated by the sensor board 6, by which therotational displacement of ball is detected.

FIG. 2 is an explanatory view showing a side sectional construction of arotating element and its surrounding portion of another example of atrack ball in accordance with the present invention. FIG. 2 shows anexample in a case where a reflective photosensor is used as a rotationsensor. In FIG. 2, the track ball in accordance with the presentinvention has a ball support structure 27 having a rotating shaft 3which supports a ball (not shown), being an input operation part, andtransmits the rotation of the ball and a rotating element 24 which isprovided at the end of the rotating shaft 3 to cause a rotation sensor25, described later, to read the rotation of the rotating shaft 3; therotation sensor 25 which generates a pulse signal by detecting therotation of the rotating element 24 that expresses the rotation of therotating shaft 3 and transmits the pulse signal to a sensor board 6,described later; the sensor board 6 for arithmetically operating thetransmitted pulse signal to detect the rotational displacement; and acase 22 which is a housing structure for the track ball and protectivelycontains the sensor board 6 therein. The rotating element 24 and therotation sensor 25 are provided so as to be isolated from each other bythe case 22 so that foreign matters such as water and dust can beprevented from intruding into a case interior space SI containing thesensor board 6 etc. from a ball-side space SB that is a space continuouswith the environment on the outside of the track ball. Also, of the case22, at least a case portion 22C (a closely hatched portion in FIG. 2),which isolates the rotating element 24 from the rotation sensor 25 andforms a part of an electromagnetic wave transmission path for therotation sensor 25 to detect an electromagnetic wave to be detected, hasa construction capable of transmitting an electromagnetic wave that canbe detected by the rotation sensor 25.

In FIG. 2, this track ball can be configured so that the whole of thecase 22, not limited to the case portion 22C, can have a constructioncapable of transmitting the electromagnetic wave. Also, the case 22 neednot be provided with a notch for the rotation sensor 25 to detect therotation of the rotating element 24.

In FIG. 2, the track ball has a construction such that the rotatingelement 24 has a drum shape, and the rotation sensor 25 is a reflectivephotosensor.

Unlike the track ball using a transmission photosensor as shown in FIG.1, the case 22 need not have a substantially U-shaped side crosssection. Specifically, in the track ball using the reflectivephotosensor as shown in FIG. 2, the case 22 needs neither a notch nor asubstantially U-shaped portion, which achieves an effect that the numberof processes can be decreased, and accordingly the manufacturing costcan be reduced.

In the track ball shown in FIG. 2, the rotation sensor 25, which is thereflective photosensor, is provided at a position facing to the rotatingelement 24 with the case 22 being held therebetween, and has a lightemitting portion E for emitting an electromagnetic wave to a reflectorprovided on the drum-shaped rotating element 24 and a light receivingportion R for receiving an electromagnetic wave reflected by thereflector. The ball-side space SB in which the ball support structure 27is provided and the case interior space SI in which the rotation sensor25 and the sensor board 6 are provided are isolated from each other bythe case 2 with the case 22 being a boundary. Therefore, the rotatingelement 24 and the rotation sensor 25 are provided in a state of beingisolated from each other by the case 22, and the rotation sensor 25 andthe sensor board 6 are constructed so as not to communicate with theball-side space SB, that is, so as to be isolated from the space SB.

When visible rays are utilized as the electromagnetic wave, the trackball shown in FIG. 2 can be constructed so that the construction of thecase 22 for transmit the electromagnetic wave is made a transparent orsemitransparent visible ray transmitting construction. To obtain such aconstruction, the whole of the case 22 or at least the case portion 22Ccan be constructed by using a transparent or semitransparent material.When other electromagnetic waves are utilized, similarly the case 22 canbe constructed by using the electromagnetic wave transmitting material.

When infrared rays are utilized as the electromagnetic wave, theconstruction of the case 22 for transmit the electromagnetic wave ismade an infrared ray transmitting construction. To obtain such aconstruction, the whole of the case 22 or at least the case portion 22Ccan be constructed by using an infrared transmitting material.

In FIG. 2, since the trackball in accordance with the present inventionhas the above-described construction, the rotation of the rotatingelement 24 of the ball support structure 27 provided in the ball-sidespace SB is detected through the case portion 22C capable oftransmitting an electromagnetic wave that can be detected by therotation sensor 25, for example, visible rays or infrared rays, orthrough the case 22. Specifically, in FIG. 2, when the portion E of therotation sensor 25, which is a reflective photosensor, is the lightemitting portion and the portion R thereof is the light receivingportion, the electromagnetic wave such as visible rays or infrared raysemitted from the light emitting portion E enters the drum-shapedrotating element 24 existing in the ball-side space SB region throughthe case portion 22C of the case 22, being processed by the reflectorprovided on the drum-shaped rotating element 24, and is received anddetected as a pulse signal by the light receiving portion R through thecase portion 22C. In FIG. 2, for example, on a straight line L′, thereexists a path through which visible rays etc. go from the light emittingportion E to the light receiving portion R via the case portion 22Cthrough the reflector on the drum-shaped rotating element 24.

Since the rotating element 24 need not be provided in the case interiorspace SI for the rotation sensor 25 to detect the rotation of therotating element 24, the case 22, which is the boundary between both ofthe spaces SB and SI, need not be provided with a notch for causingthese spaces SB and SI to communicate with each other. Specifically, theball-side space SB in which the ball support structure 27 is provided isisolated from the case interior space SI containing the rotation sensor25 and the sensor board 6 by the case 22. Therefore, foreign matterssuch as water and dust can be prevented from intruding into the caseinterior space SI from the ball-side space SB continuous with theenvironment on the outside of the track ball.

In other words, even if foreign matters such as water and dust, whichare originated from the environment on the outside of the track ball,are present in the ball-side space SB, the foreign matters do notintrude into the case interior space SI, which is isolated from theball-side space SB by the case 22 (X2). Therefore, the foreign mattersare prevented from intruding into the sensor board 6 and the rotationsensor 25, which are provided in the space SI.

The rotation of the rotating element 24 is detected by the rotationsensor 25 provided in the case interior space SI, and a pulse signal isgenerated by the rotation sensor 25. The pulse signal is transmitted toand arithmetically operated by the sensor board 6, by which therotational displacement of ball is detected.

Industrial Applicability

According to the track ball in accordance with the present invention,foreign matters such as water and dust can be prevented from intrudinginto the case containing the sensor board. Further, there is no need forproviding a notch in the case, so that the manufacturing cost can bereduced.

Also, according to the track ball using the reflective photosensor,there is no need for partially forming the case substantially into a Ushape, so that the manufacturing cost can further be reduced.

1. A track ball having: a ball; a ball support structure having arotating shaft which supports said ball and transmits the rotation ofsaid ball and a rotating element which is provided at the end of saidrotating shaft to cause a rotation sensor, described later, to read therotation of said ball; said rotation sensor which generates a pulsesignal by detecting the rotation of said rotating element that expressesthe rotation of said rotating shaft and transmits said pulse signal to asensor board, described later; said sensor board for arithmeticallyoperating said transmitted pulse signal to detect the rotationaldisplacement; and a case which is a housing structure for said trackball and protectively contains said sensor board therein, characterizedin that said rotating element and said rotation sensor are provided soas to be isolated from each other, and of said case, at least a portion,which forms a part of an electromagnetic wave transmission path for saidrotation sensor to detect an electromagnetic wave to be detected, has aconstruction capable of transmitting an electromagnetic wave that can bedetected by said rotation sensor.
 2. The track ball according to claim1, characterized in that the whole of said case has a constructioncapable of transmitting said electromagnetic wave.
 3. The track ballaccording to claim 1, characterized in that said case has no notch forsaid rotation sensor to detect the rotation of said rotating element. 4.The track ball according to claim 1, characterized in that saidelectromagnetic wave is visible rays, and the construction of said casefor transmitting said electromagnetic wave is a transparent orsemitransparent visible ray transmitting construction.
 5. The track ballaccording to claim 1, characterized in that said electromagnetic wave isinfrared rays, and the construction of said case for transmitting saidelectromagnetic wave is an infrared ray transmitting construction. 6.The track ball according to claim 4 characterized in that said rotatingelement has a disc shape, said rotation sensor is a transmissionphotosensor, and the side sectional shape of said case in a portion inwhich said case is opposed to the peripheral edge portion of saidrotating element (hereinafter referred to as “rotating element portion”)is substantially in a U shape having a U-shaped portion.
 7. The trackball according to claim 4 characterized in that said rotating elementhas a drum shape, and said rotation sensor is a reflective photosensor.8. A dustproof and waterproof track ball characterized in that foreignmatters are prevented from intruding into the interior of said casecontaining said rotation sensor by the track ball according to claim 1.9. The track ball according to claim 2, characterized in that said casehas no notch for said rotation sensor to detect the rotation of saidrotating element.
 10. The track ball according to claim 2, characterizedin that said electromagnetic wave is visible rays, and the constructionof said case for transmitting said electromagnetic wave is a transparentor semitransparent visible ray transmitting construction.
 11. The trackball according to claim 3, characterized in that said electromagneticwave is visible rays, and the construction of said case for transmittingsaid electromagnetic wave is a transparent or semitransparent visibleray transmitting construction.
 12. The track ball according to claim 2,characterized in that said electromagnetic wave is infrared rays, andthe construction of said case for transmitting said electromagnetic waveis an infrared ray transmitting construction.
 13. The track ballaccording to claim 3, characterized in that said electromagnetic wave isinfrared rays, and the construction of said case for transmitting saidelectromagnetic wave is an infrared ray transmitting construction. 14.The track ball according to claim 5 characterized in that said rotatingelement has a disc shape, said rotation sensor is a transmissionphotosensor, and the side sectional shape of said case in a portion inwhich said case is opposed to the peripheral edge portion of saidrotating element (hereinafter referred to as “rotating element portion”)is substantially in a U shape having a U-shaped portion.
 15. The trackball according to claim 5 characterized in that said rotating elementhas a drum shape, and said rotation sensor is a reflective photosensor.16. A dustproof and waterproof track ball characterized in that foreignmatters are prevented from intruding into the interior of said casecontaining said rotation sensor by the track ball according to claim 2.17. A dustproof and waterproof track ball characterized in that foreignmatters are prevented from intruding into the interior of said casecontaining said rotation sensor by the track ball according to claim 3.18. A dustproof and waterproof track ball characterized in that foreignmatters are prevented from intruding into the interior of said casecontaining said rotation sensor by the track ball according to claim 4.19. A dustproof and waterproof track ball characterized in that foreignmatters are prevented from intruding into the interior of said casecontaining said rotation sensor by the track ball according to claim 5.20. A dustproof and waterproof track ball characterized in that foreignmatters are prevented from intruding into the interior of said casecontaining said rotation sensor by the track ball according to claim 6.